A number of former Justice Department officials, many from the Obama administration, filed an amicus brief in the AT&T-Time Warner merger case on Thursday, urging the judge to start an inquiry into whether the Trump administration directed Justice Department officials to block the deal.

The concern that Pres. Trump disliked the deal because of an ongoing feud with CNN, whose parent company is Time Warner, has been raised by several observers. And AT&T had sought communications between the White House and Attorney General Jeff Sessions in order to bolster its case, but last month U.S. District Judge Richard Leon, who is presiding over the case, denied that request.

An inquiry is needed to remove any doubt that the Justice Department is acting in good faith, the former officials say in the filing.

“Indeed, this case is being pursued under a cloud, with a perception — at least by some — that DOJ brought this case at the behest of President Trump in order to punish CNN for what he viewed as unfavorable coverage of his administration,” the filing reads.

It goes on to list several statements by Pres. Trump and media reports that led to the perception that Pres. Trump interfered.

The filing makes clear that the parties are just seeking an investigation and have no evidence that anyone in the White House did interfere in the case.

“To be clear, DOJ may well have acted independently and outside the cloud of any White House interference in this matter. Indeed, based on their long experience in the Department working alongside its dedicated public servants, amici hope and expect that to be the case. But when the president specifically threatens to use the power of DOJ to punish a perceived opponent, it raises serious constitutional concerns.” the filing reads.

Two of the parties listed in the amicus brief are contributors to CNN, including Preet Bharara, a former U.S. Attorney in Manhattan who was fired by Pres. Trump and is now a senior legal analyst at CNN, and John W. Dean, the Nixon White House counsel who served time in jail in the Watergate scandal. Dean is now a CNN contributor.

Sarah Saldaña, former director of U.S. Immigration and Customs Enforcement and former U.S. Attorney in Dallas, also signed on to the brief.

Others involved in the brief are Joyce Branda, former acting assistant attorney general for the Civil Division; Damon Martinez, former U.S. Attorney in New Mexico; John McKay, former U.S. Attorney in Washington; Molly Moran, former principal deputy associate attorney general; Florence T. Nakakuni, former U.S. Attorney in Hawaii; Jocelyn Samuels, former acting assistant attorney general for the Civil Rights Division; Carter Stewart, former U.S. Attorney in Ohio, and Joyce White Vance, former U.S. Attorney in Alabama.